Position and authenticate Wi-Fi users to enhance Wi-Fi security control and management

ABSTRACT

An approach is provided that receives, from a radio frequency identification (RFID) tag included with a device, at least three different charge times. Each of the charge times corresponds to a different RFID reader that separately charges the RFID tag with each of the RFID readers being at a different geographic location. A distance between each of the RFID readers and the RFID tag is approximated based on the respective charge times and these approximate distances are used to identify a geographic position of the RFID tag using trilateration. The geographic position of the RFID tag is then used to determine whether to allow the device wireless access to a computer network.

BACKGROUND OF THE INVENTION Technical Field

This disclosure relates to identifying device positions based on RFIDcharge time amounts and allowing WiFi access accordingly.

Description of Related Art

Radio-frequency identification (RFID) uses electromagnetic fields toautomatically identify and track tags attached to objects. The tagscontain electronically stored information. RFID tags collect energy froma nearby RFID reader's interrogating radio waves. Because of theirrelatively low cost, RFID tags are being included in an increasingnumber of information handling system devices. These tags can further beembedded in such devices, rather than attached to the outside of thedevice. As the name implies, passive tags wait for a signal from an RFIDreader. The reader sends energy to an antenna which converts that energyinto an RF wave that is sent into the read zone. Once the tag is readwithin the read zone, the RFID tag's internal antenna draws in energyfrom the RF waves. Because passive RFID tags do not require a powersource, such as a battery, the tags are quite reliable and have alongevity greater than most of the information handling system devicesin which they might be embedded. Due to the low cost, reliability, andlongevity of passive RFID tags, a trend is that many, if not most,information handling system devices will include such one or morepassive RFID tags.

Mobile information handling system devices often connect to a network,such as the Internet, using WiFi technology. WiFi allows devices toconnect to the network over a wireless local area network (LAN)connection. Many businesses, such as restaurants, hotels, and otherbusinesses, provide free WiFi with the aim of providing WiFiconnectivity to the businesses' customers to provide such customers witha satisfying experience when associating with such businesses. WhileWiFi connections can be password protected so that users have to enter apassword provided by the business to access the network, such passwordprotected installations require the customer to retrieve the passwordfrom the business and enter the password at the customer's device. Inaddition, most businesses refrain from frequently changing the passworddue to costs and efforts involved in changing the passwords,communicating new passwords to employees and customers, and entering newpasswords into the businesses' WiFi devices.

Many users of a business' WiFi are often not customers of the businessand, instead, are referred to as “squatters.” When near enough to thebusiness' WiFi access points and routers, a non-customer can gain accessto the WiFi either by obtaining the WiFi password, that generally is notwell protected, or because the WiFi does not require a password. Thenumber of users of a WiFi affects the speed of the WiFi connection,therefore legitimate customers of a business might experience slowspeeds due to a large number of non-customer “squatters” that are usingthe business' WiFi.

SUMMARY

An approach is provided that receives, from a radio frequencyidentification (RFID) tag included with a device, three different chargetimes. Each of the charge times corresponds to a different RFID readerthat separately charges the RFID tag with each of the RFID readers beingat a different geographic location. A distance between each of the RFIDreaders and the RFID tag is approximated based on the respective chargetimes and trilateration is performed using these approximate distancesto identify a geographic position of the RFID tag. The geographicposition of the RFID tag is then used to determine whether to allow thedevice wireless access to a computer network. Embodiments also provide asystem and computer program product that perform the aforementionedapproach.

The foregoing is a summary and thus contains, by necessity,simplifications, generalizations, and omissions of detail; consequently,those skilled in the art will appreciate that the summary isillustrative only and is not intended to be in any way limiting. Otheraspects, inventive features, and advantages of the present inventionwill be apparent in the non-limiting detailed description set forthbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features, and advantages made apparent to those skilled in theart by referencing the accompanying drawings, wherein:

FIG. 1 depicts a block diagram of a processor and components of aninformation handling system;

FIG. 2 is a network environment that includes various types ofinformation handling systems interconnected via a computer network;

FIG. 3 is a diagram depicting a system using RFID charge times toidentify device locations to determine whether devices are within anarea of interest where WiFi access is provided;

FIG. 4 is a flowchart showing high-level steps taken by a process thatidentifies locations of devices based on RFID charge times;

FIG. 5 is a flowchart showing steps taken at a device RFID tag thatinforms an RFID reader of the time taken to charge the RFID tag;

FIG. 6 is a flowchart showing steps taken to determine a distancebetween a device equipped with an RFID tag and a RFID tag reader basedon the time taken to charge the RFID tag; and

FIG. 7 is a flowchart showing steps taken to identify a device'sposition in relation to an area of interest based on calculatingdistances received from the RFID tag embedded in the device to at leastthree different RFID readers.

DETAILED DESCRIPTION

FIGS. 1-7 show an approach that identifies a position of a device basedon an RFID tag included in the device. The RFID tag is separatelycharged by a set of three or more RFID readers with the RFID tagreporting the amount of time taken to charge the RFID tag. The amount oftime needed to charge the RFID tag is used to approximate the distancebetween the RFID tag and the respective RFID reader, with more timeneeded to charge the RFID tag when the RFID tag is further from the RFIDreader. When approximate distances are computed between the RFID tag andeach of three or more RFID readers, trilateration is used to identifythe geographic position of the RFID tag, and hence the device that hasthe RFID tag embedded or otherwise included. The geographic position ofthe RFID tag, and device, is used to determine whether the device iswithin an area of interest, such as a business or organization (e.g.,restaurant, hotel, coffee shop, office, etc.) that provides WiFi accessto its patrons or customers. If the device is within the area ofinterest, then access to the organization's WiFi is provided. Likewise,when the device is outside the area of interest, then access to theorganization's WiFi is denied. Device locations can be repeatedlyupdated over time to ascertain if a device enters or leaves the area ofinterest, with the device being granted or denied WiFi accessaccordingly.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java, Smalltalk, C++ or the like,and conventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the FIGS. illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The following detailed description will generally follow the summary ofthe invention, as set forth above, further explaining and expanding thedefinitions of the various aspects and embodiments of the invention asnecessary. To this end, this detailed description first sets forth acomputing environment in FIG. 1 that is suitable to implement thesoftware and/or hardware techniques associated with the invention. Anetworked environment is illustrated in FIG. 2 as an extension of thebasic computing environment, to emphasize that modern computingtechniques can be performed across multiple discrete devices.

FIG. 1 illustrates information handling system 100, which is asimplified example of a computer system capable of performing thecomputing operations described herein. Information handling system 100includes one or more processors 110 coupled to processor interface bus112. Processor interface bus 112 connects processors 110 to Northbridge115, which is also known as the Memory Controller Hub (MCH). Northbridge115 connects to system memory 120 and provides a means for processor(s)110 to access the system memory. Graphics controller 125 also connectsto Northbridge 115. In one embodiment, PCI Express bus 118 connectsNorthbridge 115 to graphics controller 125. Graphics controller 125connects to display device 130, such as a computer monitor.

Northbridge 115 and Southbridge 135 connect to each other using bus 119.In one embodiment, the bus is a Direct Media Interface (DMI) bus thattransfers data at high speeds in each direction between Northbridge 115and Southbridge 135. In another embodiment, a Peripheral ComponentInterconnect (PCI) bus connects the Northbridge and the Southbridge.Southbridge 135, also known as the I/O Controller Hub (ICH) is a chipthat generally implements capabilities that operate at slower speedsthan the capabilities provided by the Northbridge. Southbridge 135typically provides various busses used to connect various components.These busses include, for example, PCI and PCI Express busses, an ISAbus, a System Management Bus (SMBus or SMB), and/or a Low Pin Count(LPC) bus. The LPC bus often connects low-bandwidth devices, such asboot ROM 196 and “legacy” I/O devices (using a “super I/O” chip). The“legacy” I/O devices (198) can include, for example, serial and parallelports, keyboard, mouse, and/or a floppy disk controller. The LPC busalso connects Southbridge 135 to Trusted Platform Module (TPM) 195.Other components often included in Southbridge 135 include a DirectMemory Access (DMA) controller, a Programmable Interrupt Controller(PIC), and a storage device controller, which connects Southbridge 135to nonvolatile storage device 185, such as a hard disk drive, using bus184.

ExpressCard 155 is a slot that connects hot-pluggable devices to theinformation handling system. ExpressCard 155 supports both PCI Expressand USB connectivity as it connects to Southbridge 135 using both theUniversal Serial Bus (USB) the PCI Express bus. Southbridge 135 includesUSB Controller 140 that provides USB connectivity to devices thatconnect to the USB. These devices include webcam (camera) 150, infrared(IR) receiver 148, keyboard and trackpad 144, and Bluetooth device 146,which provides for wireless personal area networks (PANs). USBController 140 also provides USB connectivity to other miscellaneous USBconnected devices 142, such as a mouse, removable nonvolatile storagedevice 145, modems, network cards, ISDN connectors, fax, printers, USBhubs, and many other types of USB connected devices. While removablenonvolatile storage device 145 is shown as a USB-connected device,removable nonvolatile storage device 145 could be connected using adifferent interface, such as a Firewire interface, etcetera.

Wireless Local Area Network (LAN) device 175 connects to Southbridge 135via the PCI or PCI Express bus 172. LAN device 175 typically implementsone of the IEEE 0.802.11 standards of over-the-air modulation techniquesthat all use the same protocol to wireless communicate betweeninformation handling system 100 and another computer system or device.Optical storage device 190 connects to Southbridge 135 using Serial ATA(SATA) bus 188. Serial ATA adapters and devices communicate over ahigh-speed serial link. The Serial ATA bus also connects Southbridge 135to other forms of storage devices, such as hard disk drives. Audiocircuitry 160, such as a sound card, connects to Southbridge 135 via bus158. Audio circuitry 160 also provides functionality such as audioline-in and optical digital audio in port 162, optical digital outputand headphone jack 164, internal speakers 166, and internal microphone168. Ethernet controller 170 connects to Southbridge 135 using a bus,such as the PCI or PCI Express bus. Ethernet controller 170 connectsinformation handling system 100 to a computer network, such as a LocalArea Network (LAN), the Internet, and other public and private computernetworks.

While FIG. 1 shows one information handling system, an informationhandling system may take many forms. For example, an informationhandling system may take the form of a desktop, server, portable,laptop, notebook, or other form factor computer or data processingsystem. In addition, an information handling system may take other formfactors such as a personal digital assistant (PDA), a gaming device, ATMmachine, a portable telephone device, a communication device or otherdevices that include a processor and memory.

The Trusted Platform Module (TPM 195) shown in FIG. 1 and describedherein to provide security functions is but one example of a hardwaresecurity module (HSM). Therefore, the TPM described and claimed hereinincludes any type of HSM including, but not limited to, hardwaresecurity devices that conform to the Trusted Computing Groups (TCG)standard, and entitled “Trusted Platform Module (TPM) SpecificationVersion 1.2.” The TPM is a hardware security subsystem that may beincorporated into any number of information handling systems, such asthose outlined in FIG. 2.

FIG. 2 provides an extension of the information handling systemenvironment shown in FIG. 1 to illustrate that the methods describedherein can be performed on a wide variety of information handlingsystems that operate in a networked environment. Types of informationhandling systems range from small handheld devices, such as handheldcomputer/mobile telephone 210 to large mainframe systems, such asmainframe computer 270. Examples of handheld computer 210 includepersonal digital assistants (PDAs), personal entertainment devices, suchas MP3 players, portable televisions, and compact disc players. Otherexamples of information handling systems include pen, or tablet,computer 220, laptop, or notebook, computer 230, workstation 240,personal computer system 250, and server 260. Other types of informationhandling systems that are not individually shown in FIG. 2 arerepresented by information handling system 280. As shown, the variousinformation handling systems can be networked together using computernetwork 200. Types of computer network that can be used to interconnectthe various information handling systems include Local Area Networks(LANs), Wireless Local Area Networks (WLANs), the Internet, the PublicSwitched Telephone Network (PSTN), other wireless networks, and anyother network topology that can be used to interconnect the informationhandling systems. Many of the information handling systems includenonvolatile data stores, such as hard drives and/or nonvolatile memory.Some of the information handling systems shown in FIG. 2 depictsseparate nonvolatile data stores (server 260 utilizes nonvolatile datastore 265, mainframe computer 270 utilizes nonvolatile data store 275,and information handling system 280 utilizes nonvolatile data store285). The nonvolatile data store can be a component that is external tothe various information handling systems or can be internal to one ofthe information handling systems. In addition, removable nonvolatilestorage device 145 can be shared among two or more information handlingsystems using various techniques, such as connecting the removablenonvolatile storage device 145 to a USB port or other connector of theinformation handling systems.

FIG. 3 is a diagram depicting a system using RFID charge times toidentify device locations to determine whether devices are within anarea of interest where WiFi access is provided. Area of interest 300 canbe any geographic area, such as a restaurant, hotel, coffee shop,office, etc. The operators of the area of interest wish to providewireless, or WiFi, access to devices within the area of interest anddeny access to devices that are outside the area of interest. Mobiledevices 340 and 350, such as tablet computer systems, laptop computersystems, smart phones, or the like, have a radio frequencyidentification (RFID) tag embedded or otherwise included in suchdevices. Being passive tags, these RFID tags are charged by collectingenergy from radio waves transmitted from RFID readers 310, 320, and 330.The RFID tag records the amount of time needed to charge the RFID tagand transmits the RFID tag's identifier and the amount of charge timeback to the RFID reader. The amount of charge time is then used toapproximate a distance between the RFID reader and the RFID tag.

Three or more RFID readers are used with each reader receiving theapproximate distance from the respective RFID reader to the RFID tag.The geographic location of the three RFID readers is known so that wheneach of the readers receives the distance to the RFID tag, trilaterationcan be used to identify the position of the RFID tag, and thus theposition of the device. In the example shown, device 340 isapproximately 2.5 meters from RFID reader A (310), 1.5 meters from RFIDreader B (320), and 3.8 meters from RFID reader C (330). Trilaterationusing these distances and the known geographic locations of therespective RFID readers results in the identified location of device 340being at the geographic location show which is within the geographicarea of interest. Consequently, device 340 is granted wireless access tothe computer network, such as computer network 200 shown in FIG. 2, viaWiFi controller 360 (e.g., a wireless access point, a wireless router,etc.). Likewise, device 350 is shown being approximately 5 meters fromRFID reader A (310), 3.5 meters from RFID reader B (320), and 2 metersfrom RFID reader C (330). Trilateration of these distances using theknown geographic locations of the respective RFID readers results in theidentified location of device 350 being at the geographic location showwhich is outside the geographic area of interest. Consequently, device350 is denied access to the computer network via WiFi controller 360.

FIG. 4 is a flowchart showing high-level steps taken by a process thatidentifies locations of devices based on RFID charge times. FIG. 4processing commences at 400 and shows the steps taken by a locationwizard process that gathers data needed to identify locations of RFIDtags included in wireless devices requesting WiFi access. At step 405,the process selects data pertaining to the first RFID reader that isbeing controlled by the process. The data regarding the RFID readers isretrieved from data store 410. At step 415, the process sends aninstruction to the selected RFID reader that instructs the RFID readerto gather RFID data from any RFID tags within range of the reader. Atstep 420, the process waits for a time period to elapse. The time periodis set to a period that is long enough to allow the selected RFID readerto transmit radio waves to any RFID tags within range of the reader,fully charge the RFID tags, and receive responsive data from the RFIDtags. The responsive data will include the identifiers of the RFID tagsas well as the amount of time needed, or taken, to fully charge the RFIDtag by the selected RFID reader.

Once the time period set in step 420 elapses then, at step 425, theprocess sends an instruction to the selected RFID reader to stopgathering data. This quiets the RFID reader so that the reader no longertransmits radio waves. Quieting the RFID readers that are not currentlygathering data allows each RFID reader, when selected, to communicatewith the RFID tags without interference from other RFID readers so thata distance can be approximated between each of the RFID readers and theRFID tags that are within range. The process determines as to whetherthere are more RFID readers to select for receiving data from RFID tags(decision 430). In order to perform trilateration to identify theposition of the RFID tags, at least three RFID readers are typicallyused. If there are more RFID readers to select, then decision 430branches to the ‘yes’ branch which loops back to step 405 to select andprocess the next RFID reader as described above. This looping continuesuntil all of the RFID readers that are being used have been selected, atwhich point decision 430 branches to the ‘no’ branch whereupon, at step435, the process resets the RFID reader to the first reader and startsthe process over again by looping back to step 405. Accordingly, thisprocess operates continually.

RFID reader processing commences at 440 and shows the steps taken by theRFID reader that has been selected by the location wizard. Each of theRFID readers, when selected, perform steps 445 through 480. At step 445,the process receives the instruction from the location wizard to contactany RFID tags in range of this RFID reader. At step 450, the RFID readerprocess clears memory 455 that is used to store data gathered from theRFID tags that are in range of the reader. At step 460, the RFID readerprocess transmits radio waves in order to scans the area for all RFIDtags that are within range of this RFID reader. The radio waves provideenergy and charge the RFID tags with the RFID tags, when fully charge,transmitting the identifier of the respective RFID tag along with theamount of time taken to charge the respective RFID tag. As will be morefully explained infra, the amount of time taken to charge the RFID tagis used to approximate the distance between the RFID reader and the RFIDtag. At step 465, the RFID reader process receives and stores data fromRFID tags. This data includes the RFID tag's identifier and the amountof time taken to charge the RFID tag. In one embodiment, the data alsoincludes the identifier of the device that is associated with the RFIDtag, such as a media access control (MAC) address of the device. Thedata received at the RFID reader is stored in memory area 455.

The RFID reader process determines as to whether a stop instruction hasbeen received from the location wizard process (decision 470). If a stopinstruction has not been received, then decision 470 branches to the‘no’ branch which loops back to step 460 to continue scanning the areaaround the RFID reader for data regarding nearby RFID tags. This loopingcontinues until a stop instruction is received from the location wizard,at which point decision 470 branches to the ‘yes’ branch exiting theloop. At step 475, the RFID reader process sends the data gathered bythe RFID reader that has been stored in memory area 455 back to thelocation wizard. At step 480, the RFID reader process enters a waitstate and waits until it receives another instruction from the locationwizard to once again scan the area for RFID tags that are within range,at which point processing loops back to step 445 to restart the process.

Location wizard processing that identifies device locations commences at485 and shows the steps taken by a location wizard process thatidentifies device locations based on data returned by the RFID tagsincluded with such devices. Predefined process 490, is the IdentifyDevice Locations routine (see FIG. 6 and corresponding text forprocessing details). This routine receives data gathered by an RFIDreader and checks to see if enough data has been gathered to performtrilateration to identify the location of the device. At step 495, theprocess repeats predefined process 490 whenever data arrives fromanother RFID reader. This process used to identify device locationsoperates continually.

FIG. 5 is a flowchart showing steps taken at a device RFID tag thatinforms an RFID reader of the time taken to charge the RFID tag. FIG. 5processing commences at 500 and shows the steps taken the RFID tag thatis included in a device. At step 510, the RFID tag wakes up when energyreceived from RFID reader in the form of radio waves transmitted fromthe RFID reader. At step 520, the RFID tag starts a timer. At step 530,the RFID tag continues receiving energy from RFID reader. Decision 540depicts a loop that operates until the RFID tag is fully charged. Theamount of time needed to fully charge the RFID tag is based on thedistance between the RFID tag and the RFID reader that is transmittingthe radio waves. Once the RFID tag is fully charged then, at step 550,the RFID tag stops the timer and computes elapsed time that was taken tofully charge the RFID tag. At step 560, the RFID tag transmits this RFIDtag's identifier and the amount of time that was taken to charge theRFID tag. In one embodiment, the RFID tag also transmits the device'sidentifier, such as the device's MAC address. The transmitted data isreceived by the RFID reader that transmitted the radio wave (thecurrently selected RFID reader as shown in FIG. 4). At step 595, theRFID tag process ends and, once radio waves are no longer beingtransmitted from the RFID reader, the charge of the RFID tag quicklydissipates.

FIG. 6 is a flowchart showing steps taken to determine a distancebetween a device equipped with an RFID tag and a RFID tag reader basedon the time taken to charge the RFID tag. FIG. 6 processing commences at600 and shows the steps taken by the location wizard process thatidentifies device locations based on the locations of the RFID tagsincluded in such devices. At step 610, the location wizard processreceives gathered data from one of the system's RFID readers. At step620, the location wizard process retrieves the identifier of the RFIDreader from which the data was received (e.g., readers A, B, or C asshown in FIG. 3, etc.). At step 625, the location wizard process selectsthe first device entry (ID) and amount of charge time that was receivedfrom the RFID reader (e.g., memory area 455 shown in FIG. 4, etc.).

At step 630, the location wizard process computes an approximatedistance between the RFID tag and the RFID reader based on the amount ofcharge time included in the RFID tag data. In one embodiment, graph 640is used to make the approximation with distance and charge times beingdiscovered through experimentation. In the graph, a charge time of onesecond corresponds to an approximate distance of three meters from theRFID reader, while a charge time of six seconds corresponds to adistance of four meters between the reader and the RFID tag. At step650, the location wizard process updates table 660 with the RFID readeridentifier, the device identifier, and the approximate distance betweenthe reader and the RFID tag as found by step 630. If data from the samedevice identifier and reader identifier is already in table 660, thenthe data is updated with the distance computed by step 630.

The location wizard process determines whether this device identifierhas at least three entries in table 660 indicating distance data from atleast three different RFID readers (decision 670). If the deviceidentifier has at least three entries, then decision 670 branches to the‘yes’ branch to perform predefined process 680. On the other hand, ifthe device identifier does not yet have at least three entries in table660, then decision 670 branches to the ‘no’ branch bypassing predefinedprocess 680. At predefined process 680, the location wizard processperforms the Identify Device Position routine (see FIG. 7 andcorresponding text for processing details). The location wizard processdetermines whether there are more entries that have been received fromthe RFID reader that need to be processed (decision 690). If there aremore entries that have been received from the RFID reader that need tobe processed, then decision 690 branches to the ‘yes’ branch which loopsback to step 625 to select and process the next set of data receivedfrom the RFID reader. This looping continues until there are no moreentries that need to be processed, at which point decision 690 branchesto the ‘no’ branch exiting the loop. FIG. 6 processing thereafterreturns to the calling routine (see FIG. 4) at 695.

FIG. 7 is a flowchart showing steps taken to identify a device'sposition in relation to an area of interest based on calculatingdistances received from the RFID tag embedded in the device to at leastthree different RFID readers. FIG. 7 processing commences at 700 andshows the steps taken by the location wizard process that identifies adevice's geographic position based on distance data between the deviceand the RFID readers. At step 720, the process uses the known geographiclocations of the RFID readers and calculates the device's geographicposition based on distances between the RFID readers and the RFID tag.This geographic position can then be compared to the area of interest.The location wizard process determines whether the device is currentlywithin the area of interest (decision 740). If the device is currentlywithin the area of interest, then decision 740 branches to the ‘yes’branch whereupon, at step 760, the process performs activities fordevices within the area of interest (e.g., allow the device wirelessaccess to the network by adding the device to a whitelist, grant accessto the WiFi, etc.). On the other hand, if the device is currentlyoutside the area of interest, then decision 740 branches to the ‘no’branch whereupon, at step 780, the process performs activities fordevices outside the area of interest (e.g., deny wireless access to thedevice by adding the device to a blacklist, prohibit access to the WiFi,etc.). FIG. 7 processing thereafter returns to the calling routine (seeFIG. 6) at 795.

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that,based upon the teachings herein, that changes and modifications may bemade without departing from this invention and its broader aspects.Therefore, the appended claims are to encompass within their scope allsuch changes and modifications as are within the true spirit and scopeof this invention. It will be understood by those with skill in the artthat if a specific number of an introduced claim element is intended,such intent will be explicitly recited in the claim, and in the absenceof such recitation no such limitation is present. For non-limitingexample, as an aid to understanding, the following appended claimscontain usage of the introductory phrases “at least one” and “one ormore” to introduce claim elements. However, the use of such phrasesshould not be construed to imply that the introduction of a claimelement by the indefinite articles “a” or “an” limits any particularclaim containing such introduced claim element to inventions containingonly one such element, even when the same claim includes theintroductory phrases “one or more” or “at least one” and indefinitearticles such as “a” or “an”; the same holds true for the use in theclaims of definite articles.

What is claimed is:
 1. A method implemented by an information handlingsystem that includes a processor and a memory accessible by theprocessor, the method comprising: receiving, from a radio frequencyidentification (RFID) tag included with a device, at least threedifferent charge times, each of the charge times corresponding to adifferent RFID reader, and wherein each of the RFID readers is at adifferent geographic location; approximating a distance between each ofthe RFID readers and the RFID tag based on the respective charge times;calculating a geographic position of the RFID tag using trilaterationbased on the approximate distances to each of the three RFID readers atthe different geographic locations; and determining whether to allow thedevice wireless access to a computer network based on the geographicposition of the RFID tag.
 2. The method of claim 1 further comprising:mapping the geographic position of the RFID tag, wherein the mappingincludes a map of an area of interest and the geographic location ofeach of the RFID readers, wherein the determination of whether to allowthe device wireless access is based on whether the geographic positionof the RFID tag is within the area of interest.
 3. The method of claim 2further comprising: in response to the geographic position of the RFIDtag being within the area of interest, including a device identifiercorresponding to the device in an access control list that allows thedevice wireless access to the computer network; and in response to thegeographic position of the RFID tag being outside the area of interest,including a device identifier corresponding to the device in an accesscontrol list that disallows the device wireless access to the computernetwork.
 4. The method of claim 1, wherein the at least three RFIDreaders include a first RFID reader, a second RFID reader, and a thirdRFID reader, and wherein the method further comprises: charging the RFIDtag from the first RFID reader during a first period during which thesecond and third RFID readers are not sending out charges; receiving,from the RFID tag, an identifier corresponding to the RFID tag and afirst charge time indicating a first amount of time taken to charge theRFID tag from the first RFID reader; charging the RFID tag from thesecond RFID reader during a second period during which the first andthird RFID readers are not sending out charges; receiving, from the RFIDtag, the identifier corresponding to the RFID tag and a second chargetime indicating a second amount of time taken to charge the RFID tagfrom the second RFID reader; charging the RFID tag from the third RFIDreader during a third period during which the first and second RFIDreaders are not sending out charges; and receiving, from the RFID tag,the identifier corresponding to the RFID tag and a third charge timeindicating a third amount of time taken to charge the RFID tag from thethird RFID reader.
 5. The method of claim 4, further comprising:approximating a first distance between the RFID tag and the first RFIDreader based on the first charge time, a second distance between theRFID tag and the second RFID reader based on the second charge time, anda third distance between the RFID tag and the third RFID reader based onthe third charge time.
 6. The method of claim 4 further comprising:storing an entry in a memory area corresponding to each of the first,second, and third charge times; and performing the calculating step inresponse to detecting, by a controller, that at least three entries fromdifferent RFID readers have been stored in the memory corresponding tothe RFID identifier.
 7. The method of claim 1 further comprising:determining to allow the device wireless access to the computer networkin response to a first determination that the RFID tag is within an areaof interest; after a period of time, re-performing the receiving,approximating, and calculating steps a second geographic position of theRFID tag; determining that the second geographic position is outside thearea of interest; and inhibiting the device wireless access to thecomputer network in response to the determination that the secondgeographic position of the RFID tag is outside the area of interest.